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What Are 5 Whys in Six Sigma?

The 5 Whys

What Are 5 Whys in Six Sigma?

Six Sigma is a set of techniques for process improvement developed by Bill Smith at Motorola in the 1980s. The 5 Whys method is much older, and was being used by Toyota as early as the 1930s. Today, the 5 Whys technique is commonly used as part of Six Sigma processes because it has proven to be a useful tool for continuous improvement. Six Sigma seeks to reduce process variation so that products or services meet customer expectations with fewer defects. The guiding principle of Six Sigma is that problems can be identified and eliminated if processes are measured and controlled.  But what are the 5 Whys in Six Sigma and how does this method work to reduce problems and defects? 

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What Is the 5 Whys Technique?

The 5 Whys technique is a problem-solving method used to uncover the root cause of an issue. It is based on the principle that asking “why” five times will help get to the problem’s core. The initial premise of this technique is that by repeatedly asking “Why?” you can dig deeper and deeper into the cause-and-effect chain leading to a given problem until you arrive at a fundamental root cause. 

With this technique, it is essential to ensure that each answer brings up another “why” question that requires further investigation and exploration. Each level needs to be explored for it to be effective. As individuals explore various “why” questions, they may find new information or identify different causes than were initially considered.

Using the 5 Whys technique can help you quickly identify and resolve problems or issues, reducing the time and effort needed to solve them. 

Why Is the 5 Whys Technique Important in Six Sigma?

The DMAIC process (Define, Measure, Analyze, Improve, Control) is a structured approach for problem-solving and process improvement used widely in Six Sigma methodology. It is an iterative cycle of five phases, within which specific tools and techniques characterize each step.

  1. The Define phase requires a clear understanding of the project and its goals. 
  2. The Measure phase involves collecting data to quantify the current performance of the process in question and identify areas that require improvement. 
  3. In the Analyze phase, teams analyze available data to determine the root causes for any problems or opportunities identified. 
  4. During the Improve phase, changes are made to improve the process by applying the best solutions. 
  5. The Control phase monitors and maintains process improvement over time to ensure gains are sustained over the long term.


Problem: The DMAIC process is an effective problem-solving tool, but it can take time to identify the root cause of a problem.

Agitate: Identifying the true source of a problem is necessary to create an effective solution that will prevent the issue from recurring.

Solution: The 5 Whys technique is a great way to get to the root cause of any issue quickly and efficiently. 

The 5 Whys technique requires careful thought and analysis to be successful. By asking why something is happening, the team can uncover previously unknown facts. 

How to Use the 5 Whys in Six Sigma

Here are some tips for effectively using the 5 Whys technique:

  1. Start by identifying a problem that needs to be solved.
  2. Focus on the desired outcome while coming up with possible solutions.
  3. Analyze each potential solution and determine which fits your problem best.
  4. Assess the feasibility of each solution and use data-driven decision-making to choose the best option.
  5. Create a plan of action to implement the chosen solution, and consider enlisting help from others if necessary.
  6. Monitor the progress and make adjustments as needed.
  7. Track the results to determine if the desired outcome is achieved or if further changes are required.
  8. Document the entire process for reference in the future, and use what you have learned to inform other problem-solving solutions


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Real-World Applications:

The 5 Whys technique is a valuable tool for problem-solving and root cause analysis in various industries.

For example, in the manufacturing industry, this technique can identify the source of defects or errors in a production line. Asking the question ‘Why?’ multiple times will eventually lead to an answer that explains why the fault or error occurred.

The 5 Whys technique can be applied to customer feedback data in the service sector. By asking ‘Why’ five times regarding customer complaints or requests can help uncover underlying problems and issues affecting customer satisfaction. This information helps make improvements that will increase customer satisfaction.

It is helpful in engineering projects during troubleshooting and debugging processes. By working through layers of questions related to an issue or bug, engineers can determine what caused it and how best to solve it.

Get Better Results with Our 5 Whys Tool

Access our free template to implement this powerful problem-solving methodology in your projects. To get help for your team in putting Six Sigma methods into practice, contact our experts today.